Genetic Engineering, Cell Structures, and Key Differences
Genetic Engineering
Genetic engineering is a science that occupies the manipulation of genetic material. The human genome is the complete sequence of DNA.
Techniques
- Recombinant DNA: A gene is inserted into a plasmid (circular DNA different from bacterial chromosome). Before the DNA has been cut with restriction enzymes, it is a way to clone the bacterial gene. Applications: Synthesis of medicines (insulin, coagulation factors, growth hormone, interferon, vaccines), livestock (cows with less fat), in agriculture (wheat and larger plants resistant to pests and herbicides), and to treat hereditary diseases. Problems: Ethical and moral. In the case of transgenic plants, we do not know the long-term effects and if they can produce diseases.
- PCR Technique: It is used to amplify DNA, using a device called a thermocycler. When you get a lot of cycles of DNA samples, it can be used in the study of evolution, in police investigations, in paternity tests, and in the production of vaccines.
Chloroplasts
Chloroplasts are specific to plant cells. They have an external and internal membrane, the stroma, and thylakoids where the photosystems are (the thylakoids are stacked to form grana). They have their own DNA. Photosynthesis takes place in the stroma (dark phase or Calvin cycle) and in the thylakoids (light phase).
Mitochondria
Mitochondria have an external membrane, an internal membrane with folds, an intermembrane space, and a matrix. They contain DNA, RNA, ribosomes, and the enzyme RUBISCO. In the matrix, beta-oxidation of fatty acids and the Krebs cycle are performed. In the folds, cellular respiration takes place.
Differences Between Chloroplasts and Mitochondria
Chloroplasts are organelles of plant cells. Mitochondria are organelles of eukaryotic cells. Chloroplasts and mitochondria have a double membrane, but in chloroplasts, the inner membrane does not have crests. In chloroplasts, there are thylakoid structures immersed in the stroma, which do not appear in mitochondria. Chloroplasts are located around the cytoplasm, and mitochondria are located near the nucleus or next to the cell wall. The function of chloroplasts is photosynthesis, and that of mitochondria is cellular respiration. Within the inner membrane of the chloroplasts is the stroma, which is equivalent to the mitochondrial matrix. Both share the same origin (endosymbiotic theory).
Differences Between Plant and Animal Cells
Plant cells are larger and have a prismatic shape, while animal cells have a rounded shape. The animal cell has no cell wall or plasmodesmata, while the plant cell does. The animal cell has a centrosome, and the plant cell does not. In the animal cell, the nucleus is central, and in the plant cell, it is lateral. The animal cell has more mitochondria than the plant cell. The plant cell has chloroplasts, and the animal cell does not. Animal cells move, and plant cells do not. Plant cells have larger and more numerous vacuoles. The nutrition of plant cells is autotrophic, and that of animal cells is heterotrophic.
Differences Between Prokaryotic and Eukaryotic Cells
Eukaryotic cells are those of animals, plants, protozoa, and fungi. Prokaryotic cells are those of bacteria and cyanobacteria. The former are multicellular, and prokaryotes are unicellular. Eukaryotic cells are larger and have a nuclear membrane, organelles, and membranes. They have nucleoli, plant cell walls, and cell walls, but they do not exist in animal cells. Prokaryotic cells have no cytoskeleton, and their metabolism is aerobic and anaerobic, while in eukaryotes, the metabolism is aerobic. Prokaryotic cells have no membrane-bound organelles, and their DNA is circular, while eukaryotic DNA is linear. Prokaryotes have only one chromosome, while eukaryotes have more than one chromosome. The respiratory enzymes in prokaryotes are located in the plasma membrane, while in eukaryotic cells, they are in the mitochondria. Eukaryotic cells divide by mitosis, and prokaryotic cells divide by binary fission. The RNA and proteins in prokaryotes are synthesized in the same place, while in eukaryotes, proteins are synthesized in the cytoplasm and RNA in the nucleus.